Mechanical locking device for pressure pads



F. J. RODE MECHANICAL LOCKING DEVICE FOR PRESSURE PADS Filed June e 1927s ts$heet 1 Oct. 30, 1928. 1,689,501

F. J. RODE MECHANICAL LOCKING DEVICE FOR PRESSURE PADS Filed June 6,1927 3 Sheets-Sheet 2 Oct. 30, 1928', v

F. J. RODE MECHANICAL LOCKING DEVICE FOR PRESSURE PADS Filed June 1927 sSheets-Sheet 3 Patented Oct. 30, 1928.

UNITED STATES PATENT OFFICE.

FREDRICH J. BODE, OF CHICAGO, ILLINOIS, ASSIGNOR-TO MABQUETTE TOOL &MFG. I

COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

MECHANICAL LOCKING DEVICE FOR PRESSURE PADS.

Application filed June 6, 1927. Serial No. 196,792.

This'invention relates to improvements in mechanical locking devicesforpressure pads particularly adapted, though not necessarily limited inits use in double action sheet metal working presses, and one of theobjects of theinvention is to provide improved means for looking ormaintaining the pressure pad at the limit of its lowermost movement. toprevent the same from directly following the ram when the latter startson its return movement.

A further object is to provide an improved lockingdevice of thischaracter which will be automatically rendered active and also inactiveat predetermined times in the cycle of operation of the press.

To the attainment of these ends and the accomplishment of other new anduseful objects as will appear, the invention consists in the features ofnovelty in substantially the construction, combination and arrangementof the several parts hereinafter more fully described and claimed andshown in the accompan ing drawings illustrating this invention, an inwhich- Figure 1 is a front elevation of a double action sheet metalpress, having a locking device constructed .in accordance with theprinciples of this invention applied thereto, the same being shownpartly in section, partly broken away and with parts omitted.

Figure 2 is an enlarged detail sectional view partly in elevation andpartly in sec tion with the parts in the position which they will assumewhen the ram reaches th limit of its lowermost movement.

Figure 3 is a-horizontal sectional view taken on line 33, Figure'2, withparts omitted and parts broken away.

Figure 4 is a detail sectionalview taken on line 44, Figure 2.

Figure 5 is a detail perspective View of one of the locking members.

Referring more particularly to the drawings the numeral designates a bed'or bolster plate of a press, 11' uprights, 12 a crank shaft connectedto which by means of links 13, is a reciprocable ram 14. This ram hasconnected with it a member 15 which co-operates with a work holdingmember 16, the latter-being mounted upon and secured to the bed plate10.

A plunger 17 having a die face 18'is connected bymeans of a link 19 witha crank shaft 20 and the plunger 17 reciprocates within the member 15.(Jo-operating with here shown as embodying c linders 24 which receive asupply 0 flui under pressure from any suitable source (not shown).Reciprocable .in the cylinders 24 are pistons (not shown) towhich pistonrods 25 are connected and these piston rods are connected with thepressure pad or plate 23 by means of ahead 26 connected with the pistonrods and which heads are secured to the pressure pad in any suitablemanner.

All of the above referred to parts are of the ordinary and well knownconstruction.

The. present invention particularly relates to the means for looking ormaintaining. the pressure pad or plate 23 in its lowermost position forpreventing the same from returning. directly with the ram as the ramstarts to ascend. To that end there is pro vided a number of lockingmembers 27, any number of which may be provided and are suitablylocated.

As the construction and operation of all of these locking members andthe parts which directly co-operate therewith is the same, thespecificdescription of one will apply equally as well to them all.

ounted upon the pressure pad or plate 23 are suitable guides 28 in whichthe looking member 27 is reciprocable preferably by means of. the guidesengaging over flanges 35 of the bell crank lever is shorter than the arm36, the arm 36 being preferably twice as long as the arm 35.

The end of the arm 35 is connected with the locking member 27 throughthe medium of a pin 37 connected with the locking memberand which entersa slot 38 in the end of the arm 35. The locking member 27 is preferablybifuricated as at 39 to receive the end of the arm 35. i V a By rockingthe lever 32 about its pivot 33 it will be manifest that the lockingmember 27 may be retracted against the stress .of the spring 31 andwhile bein so retracted the energy will be stored in t e spring so thatat a proper time in the cycle of opera tion of the press the energy thusstored in the spring 31 will operate upon the locking member 27 toadvance the same and thereby rock the lever 32 about its pivot in theopposite direction.

Mounted upon the pressure pad 23 is a member 40 having a chamber 41therein.

A collar 42 is loosely pivotally connected with the extremity of thelonger arm 36 of the bell crank lever 32 by means of pins or lugs 43which are connected with the collar 42 and enter slots 44 in the end ofthe arm 36. The extremity of the arm 36 is bifurcated as at 45 (seeparticularly Figure 3) and the collar 42 is preferably bifurcated. A rodor member 46' passes loosely through the member 40, chamber 41, pressurepad 23 and through the collar 42. The bifurcated formation of the collar42 and of the extremity of the arm 36 permit the collar 42 and arm 36 tomove freely and independent with respect to the rod 46. Connected withthe rod 46 is another collar 47 which is secured to the rod as at 48 andagainst movement with respect thereto. A resilient element, preferablyin the form of a coil spring 49 is disposed between the collars 42 and47 and encompasses the rod 46 therebetween. The spring 49 is of aninitial tension or stress less than the tension or stress of the spring31 so as not to interfere with the operation of the s ring 31. At theproper time in the cycle 0 operation of the press energy is stored inthe spring 49 sufiicient to momentarily overcome the stress of thespring 31 so as to retract the locking member 27 against the stress ofthe spring 31 after which operation the springs 31 and 49 will equalizeor counterbalance each other.

Connected with a reciprocable part of the I press, preferably the ram14, is a rod 50 which depends therefrom and has connected to the lowerend thereof by means of a shouldered sleeve 51, a threaded sleeve 52.The sleeve 51 is connected to the rod 50 preferably by means of a pin 53and the sleeve 52 is provided with internal screw threads.

A rod section 54 is rovided with a reduced threaded extremlty 55 adaptedto be threaded into the sleeve 52, and the lower extremity of the rodsection 54 is preferably slightly beveled as at 56 to co-operate (in51-52 and threaded extremity 55 for thepurpose of permitting anadjustment of the rod 54 with respect to the rod section 50 so as toproperly position the extremity 56 of the rod section 54 with respect tothe looking member 27, and to determine at what point in the cycle ofoperation of the press the locking member 27 will be projected, by thespring 31.

In operation and assuming the parts to be in the position shown inFigure 1, the pressure pad being at the limit of its upward movement andwhich movement is limited by the engagement ofthe members 40 with thelower face of the bed plate 10, and the ram 14 lowered to a positionjust before the member 15 engages the work 58, and the die member 21bein maintained in its upper position by the fliiid pressure in thecushions 24, the member 15 will upon a further lowering movement of theram 14 conv in Figure 1, the locking member 27 will be retracted and-thelower end of the rod section 54 will be positioned in front ofrthe endof the locking member 27 so that the resilient element 31 will hold theextremity of the lockingmember 27 against the side face of the rodsection 54. The friction created between these parts will not besufficient to retard or interfere with the lowering movement of thepressure pad 23.

In this position of the locking member 27 the spring 31 will be underfull tension, whereas the spring 49 will be free from tension, orsubstantially so.

After the work has been thus clamped b the members 15 and 16 the plungeror mem-- ber 17 will be lowered so that the die 18 will engage the workand co-operate with the die 21 to shape the work. As the member 17descends the member 21 will be lowered causing the pressure pad 23 to belowered against the resistance pressure in the cylinders 24, through themedium of the pins 22. As the pressure pad 23 is lowered the lockingmember 27 as well as the member 40 will be lowered, but the rod section54 will be held stationary, with the result that the end of the lockinmember 27 will slide over the side face of t e rod section 54. As soonas the surface 57 of the locking member 27 7 extremity 56 of the rodsection 54. As the pressure pad 23 is lowered and as the rod 46 andcollar 47 thereon are stationary the sleeve 42 will slide over the rod46 and the stress of the resilient element 49 (if there is any in suchelement at that time) will become Weaker.

When the member 27 is moved forwardly under the end of the rod section54 the longer arm 36 of the bell crank lever will be raised therebycreating energ in the resilient element 49 by placing ,t e same understress by moving the collar 42 towards the stationary collar 47. Thechamber 41 in the member.40 is Provided so as not to contact with thecollar 47 The energy in the spring 49 will continue to be built up untilthe member 40 engages the lower face of the bed plate 10 to arrest theascending movement of the pressure pad 23.

When the end of the member 27 is beneath the extremity 56 of the rodsection 54 as shown in Figure 2, the ram will be at the limit of itsdownward movement as is also the plunger or member 17, and the pressurepad 23 will then be locked against return movement as the rod sections50 and 51 will .be held stationary until the ram 14 starts to ascend. r

When the ram 14 rises .the member 15 will be raised in advance of theraising of the plunger or member 17 so that the pressure pad 23 will beretained or locked in its down.

position against directly following the ram 14 when it ascends. Afterthe ram 14 and member 15 have ascended for a short distance the-plungeror member 17 will rise and the pressure in the cylinders 24 will raisethe pressure, pad 23 until the member 40 en ages the lower face of thebed plate 10. fiuring this raising movement of the pressure pad 23 thetension on the resilient element 49 is being built up. When, however,the pressure pad 23 is arrested in its movement by the member 40engaging. the bed plate 10 a sufficient stress will be built up in theresilient element 49 to withdraw the locking member 27 from beneath the.extremity 56 of the rod section 54, the difi'erence in the leveragebetween the arms 36 and 35 of the bell crank lever 32 co-operating Vwith the resilient element 49 to overcome the stress of the resilientelement 31 tocause the locking member 27 to be withdrawn. The extremityof the locking member27 will then move along the side face of the rodsection 54.

As soon as the member 40 engages the lower face of the bed plate 10 theram will continue to ascend and with it the members or rods 54. Thewedging or binding force of the beveled or inclined end of the rodsection 54 with the inclined surface 57 of the locking member 27 willthen be released snliiciently to permit the stress in the spring orresilient element 49 to withdraw the locking member 27 against thestress in the spring 31.

While the preferred form of the invention has been herein shown anddescribed, it is connected with the said element. for move menttherewith, the said member having a shoulder adjacent said pad, a springcontrolled locking member carried with the pad and adapted to beautomatically projected beneath said shoulder to be engaged therewith atthe limit of the lower-most movement of the pad for locking the padagainst return movement, and spring influenced means rendered active bythe movement of the pad in onedirection for automatically retracting thesaid locking member at a predetermined time in the cycle of operation ofthe press.

2. A sheet metal working press embodying a pressure pad, means foryieldingly resisting the movement of the pad in one direction, areciprocable element, a member connected wit-h the said elementformovement therewith, the said member having a shoulder adjacent said pad,a spring .controlled locking member carried with the pad and adapted tobe automatically projected beneath said shoulder to be engagedthereactive at a predetermined time in the cycle' of operation of thelockingmember. v I

3. A sheet metalworking press embody ing a pressure pad movable in onedirection by the action of the ram, a member connected with the ram formovement therewith, a shoulder on said member disposed adjacent the saidpad, a locking member carried with the pad, a resilient elementoperating on said member and tending normally to project said lockingmember beneath said press to retract the said shoulder, a leverconnected Withsaid locking member for retracting it, and meansautomatically rendered active at a predetermined time in the cycleofoperation of the press and operable upon said lever to rock the sameto retract the said locking member against the stress of the saidresilient element.

4. A sheet metal working press embodying a pressure pad movable in onedirection by the action of the ram, a member connected with the ram formovement therewith, a shoulder on said member disposed adjacent the saidpad, a locking member carried with the pad, a resilient elementoperating on said member and tending normally to project said lockingmember beneath said shoulder, a lever connected with said locking memberfor retracting it, a normally inactive resilient element, and means forautomatically creating energy in the last reovercome the stress of thefirst recited resilient element to rock said lever to retract saidlocking member. a

5. A sheet metal working press embodying a pressure ad movable in onedirection retract said locking member, a normally inactive resilientelement operable upon said lever, and means responsive to the movementof the pad in one direction for creating energy in thelast saidresilient element to cause the same to temporarily overcome the stressof the said spring to retract the locking member to unlock the pressuread, the said spring and resilient element bemg then counterbalanced.

6. A sheet metal working press embodying a pressure pad movable inonedirection by the action ofthe ram, a shoulder mov-' a le with the ramadjacent said pad, a lockmg member carried by the pad, a spring normallytending to project said member beneath'said shoulder to lock the padagainst return movement, a bell crank lever pivotally connected with thepad, one arm of the lever being longer than the other, the

shorter arm of the lever being operatively connected withvthe lockingmember, normally inactive resilient means operable upon the longer armof' the lever, ,and means whereby energy will be automatically createdin the said resilient means at a predetermined time in the cycle ofoperation of the press to overcome the said spring to retract saidlocking member.

7 A sheet metal working press embodying a pressure pad movable in onedirection by the action of the ram, a shoulder movable with the ramadjacent said pad, a locking member carried by the pad, a springnormally tendin to project said member beneath said shou der to lock thepad against return movement, a bell crank lever pivotally connected withthe pad, one arm of the lever being longer thanthe other, the shorterarm of the lever being operatively connected with the locking'member,and normally inactive means responsive in its operation to the movementof the 'pad in one direction for operation upon the longer arm of saidlever to retract the locking member against the stress of said spring.

8. A sheet metal working press embodying a pressure pad, a memberprovided with a shoulder responsive to the action of a movable part ofthe press and disposed adjacent the pad, a locking member carried withthe pad, means tending normally to project said lockin member beneathsaid shoulder to lock the pad against return movement, a bell cranklever, one arm of the lever being longer than the other, meansconnecting one of said arms with the locking member, normally inactiveresilient means operable upon the other end of the arm, and meanswhereby the movement of the pad in one direction will render the saidnormallyinactive means active to create energy therein to retract thesaid locking member against the stress of the first recited means. I

9. A sheet metal working press embodying a pressure pad, a memberprovided with a shoulder responsive to the action of a-movable part-ofthe press and disposed adjacent the pad, a locking member carried withthe pad, means tending normally to project said locking member beneathsaid shoulder to lock the pad against return movement, a bell cranklever, one arm of the lever being longer than the other, meansconnecting one of said arms with the locking member, nor mally inactiveresilient means operable upon the other endof the arm, and means wherebythe movement of the pad in one direction will render the said normallyinactive means active to create ener y therein to retract the saidlocking memh of the first recited means, the fourth recited meansoperating automatically at a predetermined time in the cycle ofoperation of the press to cause the stresses of said spring and the saidresilient means to become equalized.

10. A'sheet metal working press embodyingla pressure pad, amember'providedwith a s oulder responsive to the action of a movablepart of the press and disposed adjacent the pad, a locking membercarried with the pad, means tending normally to project said lockinmember beneath said shoulder to lock t e pad against return movement, abell crank lever, one arm of the lever being longer than the other,means connecting one of said arms with the locking member, a stationarymember, a collar connected with er against the stressthe other arm ofthe lever and loosely'slidable upon the last said member, a fixed collaron said stationary member, and a norinal-' meansto retract said lockingmember.

11. A sheet metal working press embodying a pressure pad, a memberprovided with a shoulder responsive to the action ofa movable part ofthe press and disposed ad jacent the pad, a locking member carried withthe pad, means tending normally to project said lockin member beneathsaid shoulder to lock t e pad against return movement, a bell cranklever, one arm of the lever being longer than the other, meansconnecting one of: said arms with the-locking member, a stationarymember, a collar connected with "the other arm of the lever and looselyslidable upon the last said member,

a" fixed collar on said stationary member,

and a normally inactive resilient element disposedbetween said collars,the said slidable collar co-operating with the said stationary collarand operating automatically at a pre-- determined time in the movementof said pad to create energy in the said-resilient element to overcomethe" stress of the first recited means to retract said locking'member,the said "collars then co-operating to cause the stresses of the lockingmember projecting means and the said resilient element to be equalized.a

v 12. A locking device for pressure ads of sheet metal working pressesembo ying a locking member carried with the pad, resilient meansnormally tending to move the locln'ng member in one direction, a bellcrank lever carried with the pad, one arm of the lever beinglonger thanthe other, means connecting one arm of the lever with the lockingmember, a stationary guide, a'

collar movable 'freely thereupon, means connecting the collar with theother end of said lever, a second collar spaced'from the first saidcollar and secured't'o the said guide against movement with respectthereto, and

a normally inactive resilient element disposed betweenthe said collars,said collars operating at a predetermined time in the cycle of operationof said pad, to create energy in the said resilient e ement suflicientto overcome the stress of the first recited resilient means to retractthe said locking member against the stress of the latter.

13. A locking; device for pressufizpads of sheet metal working pressesem g a locking member carried with the padf esilient means normallytending to move the locking member in one direction, a bell crank levercarried with the pad, one arm of the lever. being longer than the other,means connecting one arm of the lever with the locking member, astationary guide, a collar movable freelythereupon, means connecting thecollar with the other end of said lever, a second collar spaced from thefirst said collar and secured to the said guide against movement withrespect thereto, and a normally inactive resilient element dis posedbetween the said collars, said collars operating at a predetermined timein the cycle of. operation of saidpad, to create energy in the saidresilient element sufiicient to overcome the stress of the first recitedresilient means to retract the said locking member against the stress'ofthe latter, the said collars also operating to cause the stresses of thesaid resilient means and resilient element to be substantially e ualizeddirectly after the said locking mem er has been retracted.

14. A locking device for pressure pads of sheet metal Working pressesembodying a locking member carried with the pad, resilient meansnormally tending to move the locking member in one direction, a bellcrank lever carried with the pad, one-arm of the lever being longer thanthe other,

means connecting one arm of the lever with the locking member, astationary guide,.a

collar movable freely thereupon, means connecting the collar with theotherend'ofsaid lever, a second collar spaced from the first said collarand secured to the said guide against movement with'respect thereto, andanormally inactive resilient element disposed be- I tween the saidcollars, said collars operating at a predetermined time in the cycle ofoperation of said pad, to create energy in the said resilient elementsuflicient to overcome the stress of the first recited resilient meansto retract the said locking member against the stress of the latter, allof saidparts with the exception of the said guide and stationary collarbeing movable with the said pressure jpad.

15. In a press for drawing sheet metal and the like, cushioning means, apressure pad movable against the resistance of said cushioning means, aspring influenced locking member adapted to move automatically into aposition in which to arrest the returnmovement of the pressure pad, andspring influenced means adapted to withdraw said! member from itslocking position so as to permit the pad to return to itsnormalposition. 7

In testimony whereof I have signed m name to this specification, of May,A. 13,1927.

FREDRICH J. none.

I on this 16th day Y

